Parachute



W. S. FINKEN Dec. 10, 1946.

PARACHUTE Fild Feb. 25, 1942 S Sheets-Sheet 1 Dec. 10, 1946. w. s.FINKENI PARACHUTE 5 Sheets-Sheet 5 I Filed Feb. 25. 1942 r INVENTOR.WALTER 6. F/N/l'E/V I i ATTORNEY.

Dec. 10, 1946. w, s, FlNKEN 2,412,392

PARACHUTE Filed Fb. 25, 1942 5 Sheets-Sheet 4 FIG.1 3,

FIG.14.

INVENTOR. MALTE/F a. F/lV/IE/V ATTORNEY.

Dec. 10, 1946. I I w. s FINKEN 21,412,392

PARACHUTE Filed Feb. 25. 1942 5 Sheets- Sheet s INVENTOR. WALTER 6'.FIN/(EN H W rm I ATTORNEY.

l atentecl Dec. 10, 1946 UNITED STATES PATENT OFFICE 2,412,392 PARACHUTEWalter S. Finken, Brooklyn, N. Y., assignor t6 Leonard P. Friedei, NewYork, N. Y. Application February 25, 1942, Serial No. 432,309

12 Claims. 1

This invention relates generally to parachutes and has particularreference to improvements in the construction of what is usuallyreferred to herein as the canopy of parachutes. The term canopy is usedmainly as a matter of convenience in referring to that part of aparachute which acts to support or retard the descent of various loadswhen discharged or released in the air.

A main object of the invention is to provide a canopy which can beproduced at a low cost so that if the parachute is not recovered afteruse the loss from a cost standpoint will be relatively unimportant; thisbeing effected by a novel construction which incidentally makes the newcanopies stronger and more efficient, and the parachutes as a whole moresatisfactory in use, than comparable prior parachutes. These featureshave particular importance when the parachutes are used for suchpurposes as supporting flares and signals and to retard bombs andsimilar things when dropped or released. The new canopy is substantiallyhemispherical in shape when expanded and is composed of sections ofwoven fabric or sheets of suitable flexible material. Except for heavyduty parachutes a suitable material is a long fiber paper. Thesesections of material are secured together at their edges by seams. Whilethese seams may be bonded ones, it is preferred to sew them as a matterof manufacturing convenience and because well sewed seams will not openup in packing or in service. However, sewed seams involve making rows ofneedle punctures and an important feature of the invention resides inthe construction of the sections in such a way that they may be joinedtogether with a minimum number of seams in assembling the canopy. Thelow number of seams is a desirable thing because of the saving inmaterial and weight as compared with prior parachutes, and because itfacilitates packing the parachutes in packs or containers of variouskinds.

An important incidental advantage is that the paper or correspondingmaterial may be cut with a minimum of waste of the material, the shapeof the sections being such that scrap or waste cuttings is reduced to aminimum.

Further, the construction of the sections is such that none of the seamsare located along truly radial lines or, in the case of thehemispherical canopy, along lines truly corresponding to lines oflongitude on a hemispherical shape. When a parachute opens, particularlywhen released from an airplane traveling at high speed or when it isdischarged by an explosive in any of the usual ways, the opening shockor bursting stress is mainly at right angles to such radial orlongitudinal lines and is greatest in a zone around the canopy, thecenter line of that zone being parallel to the edge or bottom of thecanopy and usually located at a distance from the edge equal to aboutone-third of the total distance from the edge to the center of thecanopy. While the seams, because of their construction and location, arenot likely to fail under ordinary conditions, seams crossing or locatedin the zone referred to are protected in a novel Way by shaping theedges of the sec-v tions meeting in that zone to provide excess materialat the edges so that when the edges have been sewn together there willbe a fullness at each side of each seam which will expand outward underair pressure and thereby relieve the seams from damaging shocks andstrains.

Another object is the provision of a novel construction for furtherprotecting the canopy from damage by the opening shock, this beingassociated with the hem or edge of the canopy. This feature will behereinafter described in detail, it being sufiicient for presentpurposes to say that it involves a way of attaching the shroud lines ofthe parachute which provides a yielding or slipping connectionpermitting a shock absorbing movement of the shroud lines and the loadthereon relative to the canopy when the load is assumed by the canopy,an incidental feature being that the hem is strengthened and reinforcedagainst damage.

With the foregoing objects and advantages in view as well as otherswhich will become apparent later on, the invention consists in a novelconstruction and relation of parts as hereinafter described, withreferences to the drawings which accompany and form a part of thisspecification; the novel features being pointed out in the claimsappended hereto.

In the drawings:

Fig. 1 is a diagram illustrating the cutting of sections for subsequentassembling.

Fig. 2 is a diagram showing how the sections of the canopy are relatedfor the final assembly.

Figs. 3 and 4 illustrate steps in the assembly of the sections into thefinal canopy.

Fig. 5 is a perspective View of a completed canopy. v

Fig. 6 is a section along the line 6-43 of Fi 5 from one edge throughthe center to the opposite edge of the canopy.

Fig. 7 is a section on the line 1--l of Fig. 5 from one edge to theopposite edge and through the center of the canopy.

Fig. 8 illustrates how the shroud lines are attached to the canopy.

Fig. 9 illustrates the construction of the seams joining the sections ofthe canopy together.

Fig. 1G is a detail on a larger scale than Figure 8 illustrating the wayof attaching the shroud lines to the canopy.

Fig. 11 is a section on the line i| of Fig. 10.

Fig. 12 is a section on the line i 2|2 of Fig. 10.

Figs. 13 and 14 illustrate diagrammatically the construction of a canopyof large diameter for supporting heavy loads. a

Fig. 15 is in part the same as Fig. 10 and illus trates the operation ofthe shock absorbing connection between the shroud lines and the canopy.

Fig. 16 illustrates a modified way of connecting the shroud lines to thecanopy.

The parachute canopies shown in the drawings have, when inflated orexpanded under load, substantially a hemispherical shape. The advantagesof this shape are set forth at length in Leonard P. Frieder and WalterS. Finken U. S. application Serial No. 422,570, filed DecemberParachutes for service under conditions where they may not be recoveredfor re-use, may be made of paper which is strong and light and they mayvary in details of construction according to the service for which theyare intended.

In the simplest form, the canopy when completed has an appearanceresembling half of the cover of a baseball so far as the shapes of thesections and the seams are concerned. This simplest form involves theuse of only three pieces of the material as hereinafter explained. Thecanopy which is illustrated in Figs. 1 to 12, inelusive, employs fivesections of the material as shown particularly in Figs. 2 and 4.

In cutting the material, one section is laid out and cut as illustratedat A in Fig. 1. This section is then out along the line 26 to divide itinto two parts, 2| and 22. This operation is repeated to provide anotherpair of parts 2| and 22. Inthe construction shown in Fig. 5, there isanother section '23 which is separately cut to provide a seamless centerfor the canopy. This is animprovement of importance, as, among otheradvantages, it does away withthe prior merging of seams at the centerand lightens the construction without weakening the canopy. Inassembling the sections the parts are first put in the relationsillustrated in Fig. 2 and the sections are then brought together asillustrated diagrammatically in Figs. 3 and 4 and the parts joined byseams, the ends 'of sections 22 first being joined by seams to thecentral section 23' and the sections 2| thenbeing joined by seams'to theedges of the section 23 and to the edges of the sections 2|, therebygiving a circumferential shape to the assemblage. The seams between thecentral section 23 and the sections 2| and 22 are all along curvedlines, none of which cross through the center of the canopy.

In the simplest form of construction mentioned above, instead of thethree parts 22, 22 and 23 a section is cut as a continuous unitextending from edge to edge'of the canopy, the sections 2|, of course,being cut off from the main or original section A along the line 20. Thethree pieces are thenjoined together by two long seams.

While no'particular sequence o f'making the 1 sphere.

4 in Fig. 3, leaving only the continuous long seams along the edges ofthe three parts for joining the parts 2| in position. This longcontinuous seam is a desirable thing for many reasons, including theadvantage it gives in manufacturing the canopies.

As will be seen from Fig. 5, there are no seams in the canopy which liealong truly radial lines or, more properly speaking, along linescorresponding to the lines of longitude on a hemi- However, the longmain seams do cross a zone which receives the initial or intermittentshock when the parachute opens under load and seams is of vitalimportance, it is preferred to g 7 join the sections 22, 22 and 23 firstas illustrated this shock may be quite a severe one, particularly Wherethe parachute is released from a highspeed airplane. This shock zone isillustrated diagrammatically in Fig. 6 of the drawings. The line ofmaximum stress or the center line of the zone is at a distance from theedge of the canopy equal to approximately one-third of the distance fromthe edge tothe center of the canopy. The shock stress will, of course,come upon the seams as well as upon the material of the sections andmeans are provided for relieving or releasing the pressure on the seamswithin that zone.

Before describing this feature it will be well to explain theconstruction of the seams joining the sections together. They are allsubstantially like the one illustrated diagrammatically at 25 in Fig. 9.The seam consists in folds of the material, the plies of material in thefold being secured by a double row of stitches. This gives a strongseam, but nevertheless the sewing involves making two rows of needlepunctures which have to be taken into consideration. This is one reasonfor the seam protecting construction shown in Fig. 6 and referred toabove. That protecting construction involves cutting the edges ofsections 2| and 22 in such a way as to leave excess material at thepoints which will fall within the stress zone above mentioned so thatwhen the seams joining sections 2| and 22 are sewed there will be afullness at each side of the seam and a slackness of the seam withinthat zone. This is illustrated more or less diagrammatically at 2 inFig. 6, the greatest amount of fullnessbeing in the Vicinity of themaximum stress line of the zone and running off to a point at eitherend;

When the canopy assumes its load these fullnesses will be inflated afteror as an incident to the opening of the canopies so that the shock ofopening is both distributed and absorbedwhich appreciably relievesstrain upon the seams. In-

addition, the inflated fuilnesses lie outside of the main configurationof the canopy, therebyaifording what are somewhat'i-n the nature of airpockets which further protect the seams when the canopy is expandedunder load. y

The edge of the canopy is folded to give plies of material at the edgeof the canopy, one way of folding being as illustrated in Frigpll. Thefolded material'is then stitched by one or more parallel rows ofstitches 27 to hold the foldedJIn'aterial-in place. In making the foldsand sewing there is left a space 28 within the hem extending around thecanopy to receive a cord 29 which is of about the length of the edgecircumference of the can- 01 3. This cord reinforces-the hem to givegreater strength and forms apart ofa shock absorbing.

connection between the canopy and the shroud lines of theparachute; 5 a

One form of this shock absorbing feature is ll} lustrated in detail inFigs IO, 11 and 15. It com-- prises a tape 3| which is folded over theedge of the canopy in such a way that the ends diverge .of the section36.

a d h e iv r in .endsare then secured .by stitches to the material ofthefcanopy. These stitches do not include or hold the cord 29 leavingthat cord free for endwise movement.

The canopy material and the tape are cut away as shown at 32 in Fig. oas to expose the cord 29. The upper ends of the shroud lines 33 aresecured to the cord 29 by any suitable form of knot or fastening. Whenthe canopy takes the shock due to openin and assuming the load on theshroud lines 33 the cord 29 hasa limited endwise movement within the hemof the canopy as the cord is pulled out slightly by-the strain on theshroud lines 33 as shown inFig. '15. The cord, therefore, will have a,slipping, frictional movement relative to the hem and this will besufficient to provide a yielding connection between the load on theshroud lines and the canopy whichwill relieve the canopy from harmfulstrain. This movement is of limited extent as the cord is secured to thehem at the points where the canopy seams meet the hem, this beingillustrated at 84 in Fig. 15. However, these movements are sufficient toconstrict the edge or the canopy to some extent forming what might betermed puckers in the hem and the material which will distribute thestrains from the shroud lines along upwardly diverging lines to thematerial of the canopy.

Instead of using a single tape 31 two tapes may be used as illustratedat 35 in Figs. 10 and 12. This latter construction hassome advantages asthe two tapes provide a reinforcement from both sides which will serveto prevent the threads from cutting the canopy material.

In constructing parachutes according to the present invention for usewhen the service requirements are not severe, the tapes 3| or 35 may beomitted. The shroud lines 33 are each simply passed through a holepierced through the plies of the hem material above the cord 29 and.then tied or otherwise secured as illustrated generally at 50 in Fig,16. In this form the folds of the hem are maintained by parallel rows ofstitches 5 l The construction illustrated in Figs. 13 and 14 is, asbefore stated, one which may be used to advantage in constructing largeparachutes, the construction shown in those figures being one which hasbeen employed in constructing relatively large parachutes. In thisconstruction there is one long section 36 which extends from edge toedge across the center of the canopy and two sections 3'! and 38 whichare in large part the same in shape as the corresponding parts Foursections of the material designated 41, 42, 4.3 and M are all alike,having arcuate edges which cooperate with the edges of the parts 36, 37and 38 in such a way that when the sections are seamed together theresult will be a canopy which is substantially hemispherical whenexpanded under load, the completed structure being illustrateddiagrammatically in Fig. 14 of the drawings. In respects other than theones just stated, the larger canopies of Figs. 13 and 14 are like theones previously mentioned.

Parachutes constructed accordin to this invention have been usedhundreds of times, many of them under much more severe conditions thanare likely to be encountered in normal service.

. They opened almost instantly when freed in the air and with nofailures of the canopies. Quick and certain opening is a very desirablecharacteristic of the new parachutes. In addition, the construction ofthe canopy is a strong one and economical to make and has all of theother advantages hereinabove specified.

While specific constructions have been described hereinabove inconsiderable detail, it is apparent that those constructions areillustrative of the invention and it is not the desire to .be limited byanything herein contained, except to the extent indicated by the claimswhich follow.

What is claimed is:

1. A parachute comprising a load retarding canopy constructed in suchmanner as to assume a hemispherical shape when expanded by airresistance, a hem around the bottom of the canopy, a continuous cordwithin the hem free to move endwise within the hem and exposed at spacedapart openings made in the material of the hem, and shroud lines havingtheir upper ends secured solely to said cord at the points where it isexposed at said openings.

2. A parachute comprising a load retarding canopy constructed in suchmanner as to assume hemispherical shape when expanded by air resistance,a hem around the bottom of the canopy consisting of a plurality of foldsof the canopy material secured in folded relation by stitches, a cordwithin the foldssecured at spaced apart points to the hem and free tomove endwise within the hem between said points and exposed at spacedapart openings made through the folds of the hem intermediate the pointswhere the cord is secured in hem folds, and a plurality of shroud linesinserted through said openings and tied at their upper ends around saidcord.

3. A parachute comprising a load retarding canopy constructed in suchmanner as to assume a hemispherical shape when expanded by airresistance, a hem around the canopy consisting of folded material of thecanopy held in folded relation by stitches, reinforcing tapes spanningthe edge of the hem and secured to the canopy at spaced apart pointsaround said hem, an endless cord within the hem attached to the hem atpoints removed from the tapes and .free to move endwise relative to thehem and said tapes, the cord being exposed at spaced apart pointsthrough openings through the hem and the tapes, and shroud lines securedat their upper ends to the cord at said openings.

4. In a parachute, a substantially hemispherical load retarding canopycomposed solely of secrtions of fabric joined directly together at theiredges by seams, said sections being so constructed that when joinedtogether a single pressure relieving fullness in the material isprovided along both sides of each seam progressively increasing fromboth directions to a maximum at those parts of said seams which cross animaginary line around the canopy at a distance from the edge of thecanopy of about one-third of the total circumferential distance from theedge of the cancpy and the center of the canopy.

5. Ina parachute, a load retarding canopy composed solely of sections offabric joined directly together by seams, the edges of said sectionsbeing so constructed that when joined together a pressure relievingfullness in the fabric is provided along both sides of each seam, saidfullnesses being confined to a zone around the canopy starting aboutone-third of the distance from the center of the canopy to the edge ofthe canopy and extending toward the outer edge of the canopy, saidfullnesses expanding to relieve the seams from damaging strains withinsaid zone :vhgn the canopy opens to retard descent of its 6. In aparachute, a load retarding canopy composed solely of sections offibrousmaterial having their edges secured directly together-by sewed seams,said sections being so constructed that when the edges are joinedtogether a pressure relieving fullness is provided along both sides ofthose parts of each seam which lie within a; zone which extends aroundthe canopy and has its longitudinal center line substantially parallelto and at a distance from the edge of the canopy of about one-third ofthe total distance between the edge and the center of the canopy, saidfullnesses each tapering off at the margins of said zone. i

'7. In a parachute, a hemispherical load retarding canopy consisting ofa main section extending from edge to edge over the center of the canopyand two side sections each less than one half of the length of the mainsection, the edges of said main section and said side sections beingcurved in such manner that they may be joined together by only two seamsextending from edge to edge up over the canopy and at a distance fromthe center of the canopy "sufiicie'n't to leave a's'eamless area aroundsaid center.

8. A parachute, comprising 'a substantially hemispherical load-retardingcanopy made up of one portion including at least one piece of parasidesof the centerwith'the'partsat the edges substantially wider than thatpart aerossthe cen- V ter of the canopy, aiida pairof similar "side portions connected to the first named portion"by seams extendingcontinuously from edgeto edge 7 of the canopy-each of said side portionscontaining' at least one' piece or material and being wholly separatefro'mlthe material of thefirst named portion, and'said side portionsbeing so formed that the seams thereof with the-first namedpontioii'ar'e the form of the seams or a baseball cover and aredisposed. uniformly inrespect to the center of the top of the canopy andspaced from said center.

9. A parachute canopy in accordance with claim 11. A parachute canopy'in accordance 'With' claim 8, whereineach ofsaid side portions is contposed of three pieces of material-seamed together,

and each of said side portions is silnilarftothe other. 1 a

'12. A parachute canopy m'attor'dancetvitn k I 7 claim 8, wherein thefirst named portion is 'oi ri posed or three separate piecesof-"matria11,m-* J eluding a center piece'and similar side pieces,seamed theretol t WALTER s. mmmit;

